This invention relates in general to fluid spray systems, and more particularly relates to a pneumatic spraying apparatus and method for use with a variety of viscous and semi-viscous materials such as paint, plaster, acoustic dry wall material, waterproofing, fireproofing and mortar for stucco application.
Pneumatic spraying apparatus, commonly known as spray rigs, have been provided for spraying work. Typically, the prior spray rigs comprise a mobile frame which carries an electric motor or gasoline engine, air compressor, fluid pump, material hopper, belts, pulleys, transmission and electric clutches for driving the compressor and pump, and a spray gun connected by hoses to the compressor and pump. The spray rigs are operated by a system which includes an electrical control for engaging and disengaging the clutches for the pump, a material shut-off valve, an adjustable air valve, and an adjustable valve in the gun for controlling spray pattern density. Certain of the units also include controls for varying the speed of the transmission which is coupled with the electric motor or gas engine.
The prior art spray rigs of the type described with the relatively complicated belts, clutches and associated transmission equipment produce a costly arrangement which is relatively difficult to maintain and repair. The prior spray rigs are also cumbersome in operation as a result of the relatively complicated system for separately controlling the pumping action and valves in the spray gun.